A next-generation mobile communication system requires a technology providing a high-speed data transmission rate to improve a voice service and low-speed data service in a conventional art and provide a variety of high-speed multimedia services. Various technologies such as broadband frequency use and a method using a multiple antenna have been conducted to achieve a high-speed data transmission rate. A system using a multiple antenna is sensitive to features of radio channel in comparison with a single-antenna system in a conventional art. Accordingly, when designing a multi-antenna system, features of radio channel are required to be accurately ascertained. A next-generation radio communication system using the above-described multi-antenna is expected to be generally used in a city where electric waves are affected by buildings, trees, and the like. Also, a next-generation radio communication system using the above-described multi-antenna is expected to be widely used for wireless high-speed data communication.
In general, a multi-antenna radio channel measurement system, referred to as a channel sounder in a conventional art, is one-way measurement system, and is divided into a transmission system and a receiving system. A one-way channel sounder in a conventional art measures a radio channel in a city or an area where traffic is complex such as an urban macro or urban micro, while moving according to a specific route using a moving vehicle. In this instance, to measure a radio channel, multi-antennas for transmission and transmission system are installed in a base station or steel tower relatively higher than surrounding buildings, and multi-antennas for receiving and receiving system are installed in the moving vehicle. Through the measurement method described above, a radio channel emitted in a base station, that is, a change of downlink radio channel in various environments according to a route of a moving vehicle is measured. As opposed to the configuration above, a receiving system and multi-antennas for receiving may be installed in a base station, and a transmission system and multi-antennas for transmission may be installed in a moving vehicle. Through this, a moving vehicle emits an electric wave for measurement while moving based on a specific route, and a base station collects measurement data of an uplink radio channel emitted by a moving vehicle.
However, a one-way radio channel measurement system and method of operating the same in a conventional art is required to sequentially operate a downlink and uplink in order to measure a number of routes in a same measurement area and in a variety of environments. For this, a measurement apparatus and antenna are required to be installed in a base station and moving vehicle, respectively, and a downlink measurement is to be performed. After the downlink measurement is complete, the measurement apparatus and antenna of each of the base station and moving vehicle are changed and installed, and an uplink measurement is to be performed. A single measurement path in the same area and environment is measured twice in the system and method described above, which is inefficient and time-consuming, increases costs and wastes human resources.
Also, features of radio channel to be measured frequently change depending on an environment. In particular, a speed of moving vehicle when measuring an uplink is not identical to a speed of moving vehicle when measuring a downlink, and thus these channels may not be measured in the same environment. Also, radio channel measurement data of each of the uplink and downlink measured as described above is not measured at the same time, same measurement point, and surrounding environment, although the same path is measured. Accordingly, collected channel data to estimate correlation between data of each of the uplink and downlink may not be accurate.
Thus, a two-way radio channel measurement system is established, and a method and system to simultaneously measure an uplink and downlink in a same environment and condition when measuring a radio channel is required. Also, a technical control method and operation method to embody the two-way radio channel measurement system is required.